Causes of Cancer

What are the possible causes of cancer in children?

The causes of most childhood cancers are not known. About 5 percent of all cancers in children are caused by an inherited mutation (a genetic mutation that can be passed from parents to their children). For example, 25 to 30 percent of cases of retinoblastoma, a cancer of the eye that develops mainly in children, are caused by an inherited mutation in a gene called RB1 (7). However, retinoblastoma accounts for only about 3 percent of all cancers in children. Inherited mutations associated with certain familial syndromes, such as Li-Fraumeni syndrome, Beckwith-Wiedemann syndrome, Fanconi anemia syndrome, Noonan syndrome, and von Hippel-Lindau syndrome, also increase the risk of childhood cancer.

Genetic mutations that cause cancer can also arise during the development of a fetus in the womb. For example, one in every 100 children is born with a genetic abnormality that increases risk for leukemia, although only one child in 8,000 with that abnormality actually develops leukemia (8).

Children who have Down syndrome, a genetic condition caused by the presence of an extra copy of chromosome 21, are 10 to 20 times more likely to develop leukemia than children without Down syndrome (9). However, only a very small proportion of childhood leukemia is linked to Down syndrome.

Source: NCI (NIH)1

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Back to: « Cancer

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Cancer Causes

The causes of most childhood cancers are not known. About 5 percent of all cancers in children are caused by an inherited mutation (a genetic mutation that can be passed from parents to their children).

Most cancers in children, like those in adults, are thought to develop as a result of mutations in genes that lead to uncontrolled cell growth and eventually cancer. In adults, these gene mutations reflect the cumulative effects of aging and long-term exposure to cancer-causing substances. However, identifying potential environmental causes of childhood cancer has been difficult, partly because cancer in children is rare and partly because it is difficult to determine what children might have been exposed to early in their development. More information about possible causes of cancer in children is available in the fact sheet, Cancer in Children and Adolescents.

Source: NCI (NIH)2

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Cancer is a group of different diseases that have the same feature, the uncontrolled growth and spread of abnormal cells. Each different type of cancer may have its own set of causes.

Source: CDC NIOSH3

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Cancer Cells

Cancer begins in cells, the building blocks of body tissues. Cells grow and divide to form new cells. When normal cells grow old or get damaged, they die, and new cells take their place. Sometimes new cells form when the body doesn't need them, and old or damaged cells don't die as they should. The extra cells often form a mass of tissue called a lump, growth, or tumor.

Source: MedLinePlus Magazine (NIH)4

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Cancer Cells

Cancer begins in cells, the building blocks that make up tissues. Tissues make up the skin and other organs of the body. Normal cells grow and divide to form new cells as the body needs them. When normal cells grow old or get damaged, they usually die, and new cells take their place.

But sometimes this process goes wrong. New cells form when the body doesn't need them, and old or damaged cells don't die as they should. The buildup of extra cells often forms a mass of tissue called a growth or tumor.

Source: MedLinePlus Magazine (NIH)5

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Viruses: Scientists know that about 1 in 5 cancers are caused by infectious agents, says Dr. Douglas Lowy of NIH’s National Cancer Institute (NCI). “Identifying these infectious agents can, in principle, lead to the prevention of these cancers if vaccines can be developed against them,” Lowy says.

Source: NIH News in Health (NIH)6

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Radiation Exposure: Radiation

Being exposed to radiation is a known cause of cancer. There are two main types of radiation linked with an increased risk for cancer:

Scientists believe that ionizing radiation causes leukemia, thyroid cancer, and breast cancer in women. Ionizing radiation may also be linked to myeloma and cancers of the lung, stomach, colon, esophagus, bladder, and ovary. Being exposed to radiation from diagnostic x-rays increases the risk of cancer in patients and x-ray technicians.

The growing use of CT scans over the last 20 years has increased exposure to ionizing radiation. The risk of cancer also increases with the number of CT scans a patient has and the radiation dose used each time.

Source: NCI (NIH)7

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Immune Suppression: Immunosuppressive Medicines

Immunosuppressive medicines are drugs that decrease the body’s immune response. For example, they may be used to keep a patient from rejecting an organ transplant. Immunosuppressive medicines are linked to an increased risk of cancer because they lower the body’s ability to keep cancer from forming.

Source: NCI (NIH)8

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Carcinogens: The substances listed below are among the most likely carcinogens to affect human health. Simply because a substance has been designated as a carcinogen, however, does not mean that the substance will necessarily cause cancer. Many factors influence whether a person exposed to a carcinogen will develop cancer, including the amount and duration of the exposure and the individual’s genetic background. Learn more about Environmental Carcinogens and Cancer Risk.

  • Aflatoxins
  • Aristolochic Acids
  • Arsenic
  • Asbestos
  • Benzene
  • Benzidine
  • Beryllium
  • 1,3-Butadiene
  • Cadmium
  • Coal Tar and Coal-Tar Pitch
  • Coke-Oven Emissions
  • Crystalline Silica (respirable size)
  • Erionite
  • Ethylene Oxide
  • Formaldehyde
  • Hexavalent Chromium Compounds
  • Indoor Emissions from the Household Combustion of Coal
  • Mineral Oils: Untreated and Mildly Treated
  • Nickel Compounds
  • Radon
  • Secondhand Tobacco Smoke (Environmental Tobacco Smoke)
  • Soot
  • Strong Inorganic Acid Mists Containing Sulfuric Acid
  • Thorium
  • Vinyl Chloride
  • Wood Dust

Source: NCI (NIH)9

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Carcinogens: Does any exposure to a known carcinogen always result in cancer?

Any substance that causes cancer is known as a carcinogen. But simply because a substance has been designated as a carcinogen does not mean that the substance will necessarily cause cancer. Many factors influence whether a person exposed to a carcinogen will develop cancer, including the amount and duration of the exposure and the individual’s genetic background. Cancers caused by involuntary exposures to environmental carcinogens are most likely to occur in subgroups of the population, such as workers in certain industries who may be exposed to carcinogens on the job.

Source: NCI (NIH)10

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Workplace Exposure: Based on well-documented associations between occupational exposures and cancer, it has been estimated that 3-6% of all cancers worldwide are caused by exposures to carcinogens in the workplace (3,4).

Source: CDC NIOSH11

Physiological Causes of Cancer

Changes (mutations) in genes occur during carcinogenesis.

Changes (mutations) in genes can cause normal controls in cells to break down. When this happens, cells do not die when they should and new cells are produced when the body does not need them. The buildup of extra cells may cause a mass (tumor) to form.

Tumors can be benign or malignant (cancerous). Malignant tumor cells invade nearby tissues and spread to other parts of the body. Benign tumor cells do not invade nearby tissues or spread.

Source: NCI (NIH)12

Causes List for Cancer

Some of the possible causes of Cancer or similar disorders may include:13

... Full Causes List for Cancer »

Genetics of Cancer

Genetic Changes and Cancer: Cancer is a genetic disease—that is, cancer is caused by certain changes to genes that control the way our cells function, especially how they grow and divide. These changes include mutations in the DNA that ...14

... More on Genetics »

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References

  1. Source: NCI (NIH): cancer.gov/ types/ childhood-cancers/ child-adolescent-cancers-fact-sheet
  2. Source: NCI (NIH): cancer.gov/ types/ childhood-cancers
  3. Source: CDC NIOSH: cdc.gov/ niosh/ topics/ cancer/ 
  4. Source: MedLinePlus Magazine (NIH): medlineplus.gov/ magazine/ issues/ summer14/ articles/ summer14pg20.html
  5. Source: MedLinePlus Magazine (NIH): medlineplus.gov/ magazine/ issues/ summer13/ articles/ summer13pg5.html
  6. Source: NIH News in Health (NIH): newsinhealth.nih.gov/ 2008/ August/ feature1.htm
  7. Source: NCI (NIH): cancer.gov/ about-cancer/ causes-prevention/ patient-prevention-overview-pdq
  8. ibid.
  9. Source: NCI (NIH): cancer.gov/ about-cancer/ causes-prevention/ risk/ substances
  10. Source: NCI (NIH): cancer.gov/ about-cancer/ causes-prevention/ risk/ hormones/ reproductive-history-fact-sheet
  11. Source: CDC NIOSH: cdc.gov/ niosh/ topics/ cancer/ 
  12. Source: NCI (NIH): cancer.gov/ about-cancer/ causes-prevention/ patient-prevention-overview-pdq
  13. Source: Algorithmically Generated List
  14. Source: NCI (NIH): cancer.gov/ about-cancer/ causes-prevention/ genetics

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Note: This site is for informational purposes only and is not medical advice. See your doctor or other qualified medical professional for all your medical needs.